Publications (2)0.84 Total impact
Article: [Observation and simulation of bi-directional spectral reflectance on different type of soils].[show abstract] [hide abstract]
ABSTRACT: Knowledge of radiative transfer over bare soils is a prerequisite to addressing vegetation canopies and predicting soil properties by remote sensing. In the present study, the change in the spectral reflectance for three soils (i. e. red soil, paddy soil and coastal saline soil) with different view zenith and azimuth angles in the visible band (620 nm) and Landsat TM4 near infrared wavebands (760-900 nm) was measured in laboratory. The results showed that soil reflectance increased with increasing off-nadir view angle for all azimuth directions and soil bidirectional reflectance was azimuthally symmetric. The reflectance was highest in backscattering direction and lowest in forward-scattering direction. The bidirectional reflectance was simulated well using the Hapke model derived from the radiative transfer theory. The root mean square errors (RMSE) were 0.003, 0.002 and 0.004 and the correlation coefficients were 0.995, 0.998 and 0.998 in simulating bidirectional reflectance in visible wavebands for red soil, paddy soil and coastal saline soil, respectively; RMSE were 0.004, 0.006 and 0.005 and the correlation coefficients were 0.997, 0.996 and 0.998 in simulating bidirectional reflectance in NIR wavebands for these soils, respectively. It is stated clearly that Hapke model could be used to simulate the whole spectra curve, then to retrieve the soil surface characteristics.Guang pu xue yu guang pu fen xi = Guang pu 06/2008; 28(5):1007-11. · 0.84 Impact Factor
Article: Assessing Reclamation Levels of Coastal Saline Lands with Integrated Stepwise Discriminant Analysis and Laboratory Hyperspectral Data[show abstract] [hide abstract]
ABSTRACT: ABSTRACTAt different times over the past 30 years in Zhejiang Province, China, the coastal tidelands have been successively enclosed and reclaimed for agricultural land use. The purpose of this work was to evaluate whether laboratory hyperspectral data might be used to estimate the physicochemical characteristics of these reclaimed saline soils. A coastal region of Shangyu City (Zhejiang Province), which was grouped into four subzones according to reclamation history, was used as the study area, and soil samples were collected in each subzone. Physicochemical analyses showed that the soils were characterized by high electrical conductivity and sand content with low organic matter; the longer the saline lands had been reclaimed, the lower were the electrical conductivity and sand content and the higher the organic matter content. These changing trends of soil chemical and physical properties were found in laboratory reflectance spectra of soil samples and their first-order derivative curves. Stepwise discriminant analysis (SDA) identified six salient spectral bands at 488, 530, 670, 880, 1400, and 1900 nm. Using derived discriminant functions for saline lands with different historical years of reclamation, classification revealed an overall accuracy from a self-test of 86.6% and from cross-validation of 89.3%. Therefore, as opposed to time-consuming field investigations, this study suggested that remotely sensed hyperspectral data could serve as a promising measure to assess the reclamation levels of coastal saline lands.Pedosphere.